M37 — Salt-and-Pepper Cluster
Open Cluster in Auriga
About
An open cluster in Auriga about 4,500 light-years away, with over 500 identified stars. At least a dozen red giants dot it, and in 2022 it became the third known open cluster with an associated planetary nebula.
Imaging tips
- About 24′ across: 1,010–1,680 mm on APS-C spans a third to half of the frame.
- For the stars, one imager recommends 30–60 second subs because they are packed so close together; 45 minutes of 3-minute subs also worked on a DSLR.
- A faint hydrogen nebulosity sits behind the bright stars; 45 minutes of DSLR data did not show it, while 10 hours of Hα in 10-minute subs did.
- M37 needs no filter for the stars themselves; Hα is only for the nebulosity.
- Best in December and January.
Facts
- Size
- 24′
- Magnitude
- 5.6
- Coordinates
- RA 5h 52.4m, Dec +32° 33′
- Framing, APS-C
- 1010–1680 mm
- Framing, full frame
- 1550–2580 mm
- Best months
- Jan, Dec
- Peak altitude
- 73° from 50°N, 88° from 35°N